Extensible pipe fitting



Patented Jan. 10, 1939 UNITED STATES PATENT OFFICE 1 Claim.

This invention relates to pipe fittings and in particular to theprovision of an extensible fitting which permits the joining of twopipes or other fittings together without requiring accuracy in therelation of the pipe ends to each other.

In plumbing, gas fitting, steam fitting, and electrical conduit work, ithas always been necessary to terminate the pipes to an accurate positionadjacent each other, with the ends of the pipes to be joined separatedwithin close or fixed limits, suitable to receive a standard union. Forinstance, in fitting up or installing a pipe line, the pipe fitter willbring his connection up to a fitting, and must be careful to cut hispipe to length so as to permit the pipe threads to seal tightly into thefittings, and at the same time, to be positioned adjacent each other ata fixed distance which is sufficient to permit the closing of the union.Often times, it is necessary to use a nipple to aid in making thisclosure. If the pipe fitter does not happen to have a nipple which fitsthe particular case at hand, he must cut and thread a nipple of speciallength. This is the greatest objection to the use of pipe unions, whichmust be applied with great accuracy, if they are to hold the pressure.In using a pipe union to make thefinal closure in a pipe line, it is notonly necessary to have the distance between the two pipes or fittings tobe joined, accurate, so that the faces of the union will fit perfectly,but it is also necessary that the axes of the pipes to be joined be inline, otherwise the sealing seats in union will not seat tight allaround. Unless the units of a union seat in a straight line, an openingwill be left between the faces on one side, and a leak will develop.

The object of this invention is to provide a special type ofself-contained extensible fitting which will not require the accuratespacing of the pipes to be joined. This special fitting is free from allfixed distances, and will accommodate any spacing between the elementsto be joined, within its range.

It is desired to provide an extensible fitting which not only willperform a perfect seal against gas, steam, or fiuid pressure when usedin pipe lines, but also to provide an extensible fitting of the sameconstruction which is adaptable for use in making connections inelectrical conduit work. In electrical conduit work, it is necessary tohave considerable mechanical strength to assure the proper protection ofthe wiring, but obviously no pressure-tight seal is required, althoughit would not be objectionable. The electrical conduit fitter has thesame difficulty in joining his pipe, in that he must be accurate inmaking his connections, as the plumber does in regular pipe fitting.

The device is so designed as to provide an element which is free fromsoft packings, such as wicking impregnated with graphite; and isdesigned with tapers which permit the closing of a relatively hardpacking upon the pipe after it has been set into the line and adjustedto take up whatever space occurs between the two elements to be joined.This fitting saves the pipe fitter a considerable amount of time, inthat all of the accuracy normally required in making the connection iseliminated, and a satisfactory union or coupling at the final closure isassured.

It is planned, of course, to make the fitting with a number of terminalforms, all of which will be adapted to the standard practices inplumbing connections.

To more clearly define the invention, and to illustrate the many formsinto which it may be incorporated, reference is made to the accompanyingdrawing, in which:

Figure l is an elevation partly broken away and sectioned, showing theextensible pipe fitting in which the fundamental construction isdisclosed, as adapted to a fitting comprising two female ends.

Figure 2 is an elevation showing the extensible fitting equipped withtwo male ends, which convert the fitting to an extensible nipple.

Figure 3 is a similar view to Figure 2, but shows the extensible fittingequipped with one male end and one female end.

Similar reference numerals refer to similar parts throughout thedrawing.

In the drawing, II is a tube which has a bore l2 therethrough, one endof which has an internal taper 13, the other end l4 being threaded witha pipe tap. This threaded end is adapted to be screwed onto a nipple orthe end of a pipe to which the extensible fitting is to be joined. Onthe outside of the tube, the tapered end has a straight machine thread!5, and the threaded end 14 has a thickened portion 16, which ispreferably knurled to form a gripping surface to receive a pipe wrenchso that it may be pulled tightly onto the nipple or end of the pipe towhich it is to be attached. Obviously, this knurled surface could bereplaced by a hexagon or octagonal surface, if desired. This knurledsurface likewise provides an easy means to turn the pipe up by hand to aposition ready to be tightened by the wrench. A complementary member ll,which is tubular in form, has a straight machine thread iii ofconsiderable length. This length is dependent upon the amount ofadjustment desired. This thread is of a diameter which is sufiicient tofit, but clear the diameter of the bore through the part H. The otherend of this complementary part I? has a thickened or offset portion i9,which is knurled for quick hand-adjustment, and to receive a pipewrench. The reason for offsetting or thickening the member at the end isin order to provide satisfactory dimensions to accommodate standard pipethreads. This thickened or ofiset end is threaded to receive a pipethread 20, formed by a pipe tap, and is adapted to screw onto the end ofthe other pipe or nipple to complete the junction of the pipes to beconnected. It is to be understood that the thread l8 on the tube i! willfreely pass through the bore E2 on the tube ii; that is, the outsidediameter of the thread it is slightly smaller than the bore i2. Thuspart ll can slide in and out of the bore l2, and is not threaded to thiselement. The end [4 of the tube ll, being screwed onto the end of theother pipe to be joined, it is necessary to seal against fluid orpressure along the thread !8 where it rests in the bore i2. Toaccomplish this, a wedgelock 2 1, preferably made of a metallic alloy,is threaded to fit the thread !8, and is tapered at 22 to fit the taperE3 in the end of tube H. The other end of the wedgelock is left with asquare-edged shoulder. This shoulder is useful to provide a hold for awrench in making or breaking the joint. To force the tapered end 22 ofthe wedgelock 2! into and against the taper IS on tube II, a nut 23 isprovided, which engages thread I 5 on tube l I. This nut is preferablymade in a circular form and knurled on its surface for quick handadjustment, but could be hexagon or octagonal, and for receiving a pipewrench for tightening it. The nut 23 has an end 2 3 bored out to closelyfit the thread 58, but is not threaded thereto. The inside surface ofthis wall 24 which is adjacent the wedgelock, is slightly formed topinch into the wedgelock, and prevent leakage at this point.

In order to make a connection between two female fittings, theextensible connection may be provided with male ends 25 and 26, as shownin Figure 2. In this instance, the male ends 25 and 26 replace thethickened ends I4 and i9 shown in Figure 1. In order to connect twoelements, one having a female end and the other a male end, theextensible fitting may be provided with a male end 25 and a female end Il, thus forming a combination between the two arrangements shown inFigure 1 and Figure 2.

In order to connect two pipes together, or any other fittings which areto complete a system, it is necessary only to run these two elementsadjacent each other at any distance within the range of the extensiblefitting. The extensible fitting as supplied, would be collapsed, thatis, the thread !8 would be pushed all the way into the bore i2, and thenut i3 and threaded wedgelock 2! would be moved back along the thread 8as far as possible, to be out of the way. The tube ii is then screwedonto the end of the pipe, the thread 28 engaging, and after being turnedon by hand as far as possible, it would be tightened with a pipe Wrench.The tube ii is then pulled outward or over the thread E8, to reach theother pipe to be connected and the thread it is engaged with the end ofthe pipe, and turned on by hand as far as possible, and then tightenedwith a pipe wrench. The distance now has been taken up, and the two endsof the extensible fitting are firmly joined to the pipes to beconnected. The wedgelock 2i is now turned along the thread !8, until itstapered end 22 engages the taper E3 on the tube H. This is tightened asmuch as possible by hand. The nut 23 which is free to slide over thethread i8, is moved over the wedgelock 2! until its thread engages thethread I5 on the tube II. This is turned on by hand as far as possible,and then tightened with a pipe wrench. The pressure applied in pullingup the nut 23 against the wedgelock 2i, pressed the packing into thetaper 3 with considerable force, causing a sealing along the taper l3,and the driving of the threads in the wedge lock 2i firmly against thethread [8 on the part H, actually reducing the inside diameter of thethread of the wedgelock, and thereby eliminating tolerance. In order toprevent leakage between the inner surface of the end wall 24 and thewedgelock 2 i, this end wall is slightly formed to pinch into thewedgelock. The wedgelock, being preferably of a metal with a plasticcharacteristic, fits into all of the surfaces within which it istrapped, and forms a solid seal at this point.

It is to be pointed out that the construction de scribed is free of allfixed dimensions, and that In the ordinary fitting known as a long jointor long screw the equivalent of thread 18 is threaded into threeelements. This does not provide an extensible joint, as it is limited tofixed dimensions, and the threading on to the pipes to be joined tendsto unscrew the fitting itself which is adjusted by solid thread, and inevery known instance, the packing itself is of such a loose plasticnature, that it does not constitute a mechanical part which may bethreaded along the pipe by itself, and the thread in the packing isformed by the pressure of the joint.

This invention contemplates the pre-threading of the wedge-lock and themovement of the packing as a mechanical element along the fitting threadbefore the seal is formed.

Having described the invention, what is claimed as new and is desired tobe secured by Letters Patent, is:

An extensible pipe coupling for insertion between two fixed elements,comprising an outer member having a conical recess at the end, anexternally threaded inner member adapted to be slidably received in saidouter member, a relatively soft metallic packing sleeve having aninternal thread to coact with the external thread of the inner member,and a nut threaded to the outer member and slidably engaging the innermember for forcing said packing ring into said conical recess, theconstruction and arrangement being such that the packing sleeve can betightened by distortion without relative shifting between the outer andinner members.

JOHN H. MUNRO.

